Process of making starch and products thereof.



CHARLES C. MOORE, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR OF ONE-HALF TO FREDERICK C. STEVENS, OF ATTICA, NEW YORK.

PROCESS OF MAKING STARCI-I AND PRODUCTS THEREOF.

No Drawing.

To all whom it may concern:

Be it known that 1, CHARLES C. Moons, a citizen of the United States,residing at Washington, in the District of Columbia, have inventedcertain new and useful Improvements in Processes of Making Starch andProducts Thereof, of which the following is a specification.

This invention relates to processes of making starch and productsthereof; and it comprises a method of making starch from potatoeswherein potatoes are coarsely comminuted, dried, reground to fine form,starch milk prepared therefrom and starch extracted from the milk, thecoarsely comminuted potatoes being advantageously treated with anenzym-arrcsting agent prior to the drying operation; and it alsocomprises as a new article comminuted desiccated potato containing anenzym-arresting material uniformly distributed therethrough and havingits natural constituents in an unhydrolyzed form and giving upongrinding and settling a greater proportion of heavy starch than similarpotato material in its natural or undesiccated condition, saidcomminuted desiccated potato material being substantially unbrowned andunblackened; all as more fully hereinafter set forth and as claimed.

Ordinary, or Irish, potatoes are of course a good starch-making materialand they are largely used for that purpose, it being customary to pulpor otherwise comminute the fresh tubers and after washing out on sievesfor the purpose of obtaining a starch milk, to gravitally separate thestarch from the milk on starch settling tables. The potato carries about75 per cent. of water and several hundred per cent. more must be appliedin the pulping process. The result is a very high dilution of thesoluble matter contained in the potato. This soluble matter approximates20 per cent. of the total dry weight of the potato. It is desirable torecover this soluble matter and prepare food products from it since itis of nutritive value while sending it to waste creates a nuisance; butits extreme dilution in the usual starch waters renders this expensiveor impracticable. A more serious ,difliculty in the usual method is thatit is in practice impossible to recover more than about 75 per cent. ofthe starch shown Specification of Letters Patent.

Application filed December 16, 1911.

Patented May 8, 1917..

Serial No. 666,161.

in the potato by analysis. Part of the loss is probably due to inclusionof fine starch granules by flock and gluten as Well as by cellulartissue which has, escaped disruption in the grinding. It is not feasibleto grind potatoes to extreme fineness by the wet methods in use as thefiber and tissue, when wet, are of a spongy nature. Another part of theloss is due to the fact that not all the starch actually present in theraw potato is in a completely ripened, dehydrated heavy form, some of itexisting in What may be called an immature form and still containingwater of constitution. These hydrated forms of starch are not as heavyas mature starch and do not separate well with it on starch tables.

*I have discovered that I can materially increase the yield ofcommercial starch from common potatoes by intercalating a drying stepbetween the first comminution or grinding of the tubers and the finalsteps of preparing starch milk and recovering starch therefrom; and canalso obtain certain other advantages. If the potatoes be coarse ground,grated, chipped or sliced and then dried, dry grinding to any finenessdesired becomes practicable. With fine dry grinding much of the starchwhich would otherwise escape settling in the starch milk because ofinclusion in cellular elements becomes recoverable on the starch tables,increasing the yield .to that extent. Furthermore, in the dryingoperation immature light hydrated starch granules lose their moisture ofconstitution and become like the starch of dry grains, heavy andsettling well in Water. This also contributes to an increase in yield.

With dry very fine potato material the amount of water necessary to washthe starch from the fibrous matter is much diminished and concomitantlythe concentration of the waste efliuent from the starch tables is muchincreased, rendering more practicable commercially its concentration forfood purposes, either as cattle food or washing the product on sievesfor the separation of the starch. This steep liquor may be drawn ofi andconcentrated or t may be run into the effluent of wash Waters used inseparating the starch. Since this efiiuent then represents all that isin the potato save the starch which has been abstracted and re moved,the concentrated product represents, so to speak, a concentrated'nitroge.neous product. It maybe employed as a I evaporating cattle food or as araw material for producing articles intended for human consumption, suchas soup stock. The eflluent may be directly evaporated down in suitableapparatus, or it may be strained, filtered or filter-pressed to recoverinsoluble matters, the clear liquid concentrated to a syrup, united withthe insoluble matters and the assemblage dried.

Potatotubers, like many other succulent vegetable tissues, contain aplurality of enzyms having functions in the vital operations of thetissues. Upon cutting or disintegration of the tuber these enzymsoperate in various ways upon the various substances present. Theseactions are deleterious to the character of material for starch makingpurposes and in drying in the present invention it is desirable that thedrying be,

hastened as muchas possible to cut short enzymic action. The drying mustof course not be at a temperature suflicient to convert, gelatinize 0rhydrolyze starch. Any hydrolyzed or converted starch cannot of course berecovered on the starch tables; neither is it a desirable component ofcommercial starch. Drying should therefore be at low temperature and asquickas possible. Any of the commercial forms of driers may be employedfor the present purposes if operated at sufficiently-low temperaturesand with sufiicient rapidity. Air drying at common temperatures with'potatoes not treated to arrest enzymic activity is "much lessdesirable.

Among the enzyme are bodies which tend to cause absorption of oxygenfrom the atmosphere with browning or blackening of the tissues andcontained starch. This discoloration is much facilitated by the presenceof iron which is inevitably dissolved from cutting tools in comminutionof the tubers. I

For the foregoing reasons it is very'advantageous to treat the potatoesduring or shortly after thefirst comminution with a body or substancehaving the power'of arresting enzymic activity. While many othersubstances, such as alkaline carbonates and hydrates in dilute solution,lime, various acids, such as sulfurous acid, etc., may be employed, Ifind that a suflioient degree of activity coupled with certain otherdesirable effects for this purpose is possessed by the bisulfites.Bisulfite of lime is particularly advantageous. Bisulfite of soda orbisulfite of calcium (bisulfite of lime) may be employed, beingsprinkled in the solid or dissolved form over the potatoes during orimmediately after the comminuting action. Very little bisulfite isneeded for the present purposes, as little as one pound of sodiumbisulfite being all that is necessary for 400. or 500 pounds ofpotatoes. The bisulfites have the further advantage for the presentpurpose in that in addition to their enzym-arresting power they alsorestrain fermentation by organisms, preventing souring by the formationof lactic acid, alcoholic fermentation and the like. This isparticularly desirable Where, for any reason, the period of drying islong. With the aid of bisulfites, the potatoes may be air dried atcommon temperatures if desired without suffering deterioration.

If the potatoes are allowed to brown or blacken in drying to any extentthe starch recovered will be off-color.

The bisulfites, for the present purposes, have a further advantage inthat they appear to facilitate the conversion of the immature forms ofstarch into the heavy, easily recoverable mature forms, therebyincreasing the yield of commercial starch. The hydrated immature formsof starch in the presence of bisulfites do not dry down to give hornyconverted products. These ac- .tions are probably due to the power ofhisulfites of combining with aldehydic and ketonic bodies. Thecarbohydrates contain aldehyde or ketone groups.

In the starch making operation the pres ence of a slight amount ofbisulfite is quite desirable since it prevents fermentation and souringoccurring during the steeping and starch recovering operation. Thepresence of sulfite .or bisulfites in the small amount used isimmaterial as regards the composi- 105 tion of the Waste Water efiluentof the tables where such eflluent from the starch tables is to beconcentrated and used as a cattle food. Should itsremoval however bedesirable, this can be easily efi'ect'ed by acidulating-the 110 liquidslightly during concentration, as by acidulating it by a littlehydrochloric acid. Using sodium bisulfite, this results in the formationof a little common salt (sodium chlorid) a gas. Or, a portion of starchmilk may be allowed to sour slightly with formation of lactic acid, andthis sour liquid may be added tothe effluent from the starch tablebefore or during concentration. The lactic 12o acid. will expel thesulfur dioxid.

In an advantageous form, of the present invention, I take potatoes andcomminute them in any suitable Way, as by chopping, grating, slicing,etc. The comminuted ma- 125 terial emerging from the machine used may besprinkled with the sodium or calcium bisulfite, and may thereafter bedried as a Whole in any convenient manner. By treating the comminutedmaterial inpregnation 130 becomes, for the present purposessubstantially uniform. In the presence of bisulfite, drying may bereadily effected in the sun or by air of normal temperature, withoutfear of souring or blackening or other fermentation or enzymic actions.Where the enzymretarding body, such as bisulfite, is absent, drying mustbe relativelyrapid and occur soon after comminution. The temperature ofdrying should be below the gelatinizing point of starch; that is, shouldnot at a maxi- ,mum go over 60 C. Air of a temperature somewhat hotterthan this may be used for drying in the first stages since the development of vapor prevents the starchy material reaching the temperature ofthe air. As the moisture evaporates, the material becomes less sensitiveto heat, and it may be finished relatively warm. However dried, itshould be in a completely dry condition. This insures dehydration ofimmature starch and allows very fine grinding in the next stage.

So dried, and particularly in the presence of the sulfite, the potatomaterial will store indefinitely or ship any distance. The dry materialis next ground to a fine flour or meal in any suitable type of mill ormachine. The

finer the grinding,ordinarily, the better are the results. The fineground material is now steeped with water, which may have a littlesulfur dioxid or bisulfite added to it. The mixture or magma is thensieved to obtain a starch milk which is then treated on tables in theusual way to recover starch.

Useful effects of the intermediate drying operation are evinced when thesulfite is not used; but for the stated reasons it is very advantageousto combine the sulfite treatment with the drying as it tends to increasethe yield of starch and give a better colored starch.

The efiiuent from the starch table may be, as stated, filtered andevaporated to a syrup, such syrup being if desired, united with thefibrous matter left in the sieves and the two dried down together. Or,as the material has been very finely ground, the efliluent coming fromthe tables may be simply concentrated as such in any type of vacuumapparatus. If the presence of a little sulfite in the material is notundesirable, as in cattle foods, it may simply be allowed to remain.Otherwise, during the concentration a little hydrochloric or lactic acid-may be used to expel the sulfur dioxid.

The bisulfite operates effectively to restrain enzymic activity duringthe operatlon and the residual bisulfite remaining in the drypreparation operates in the same manner after the regrinding when thematerial 1s once more wetted in making the starch milk. Drying at lowtemperatures, such as must be used in the present invention does notdestroy enzymic activity altogether and such activity may be resumedwhen the material is once more wetted to make the starch milk. Thepresence of the bisulfite operates to prevent this resumption ofactivity.

The treatment of sensitive succulent vegetable materials with anenzym-antagonistic chemical preparatory to drying and there after makingstarch, I do not claim broadly in the present application, it formingthe subject-matter of my prior and co-pending application Serial No.490,411.

The process of preliminarily drying succulent starch-yielding vegetablematters generally, fine-grinding while dry and then recovering thestarch after forming a starch milk, I do not claim broadly herein, thisforming the matter of certain claims in my co-pendingapplication SerialNo. 743,066, filed January 20, 1913.

What I claim is 1. The process of treating potatoes which comprisesimpregnating the same in a comminuted state with an enzym poison,desiccating the whole mass and recovering starch.

2. The process of treating potatoes which comprises impregnating thesame in a comminuted state with a composition comprising S0 desiccatingthe whole mass and recovering starch.

31 In the manufacture of valuable products from potatoes, the processwhich comprises comminuting potatoes, desiccating, regrinding,converting the reground material into a starch milk and recoveringstarch therefrom. v

4. In the manufacture of valuable products from potatoes, the processwhich comprises comminuting potatoes, desiccating in thepresence of anenzym-arresting agent, regrinding, converting the reground material intoa-starch milk and recovering starch therefrom. I

5. In the manufacture of valuable products from potatoes, the processwhich comprises comminuting potatoes, desiccating, regrinding,converting the reground material into astarch milk, recovering starchtherefrom and concentrating the effluent to form a food product.

6. In the manufacture of valuable products from potatoes, the processwhich comprises comminuting potatoes, desiccating in cated potatoescontaining a bisulfite, having their natural constituents in anunhydrolyzed light colored form and giving upon regrinding and Wetsettling a greater proportion of heavy starch than the originalundesiccated potato material.

9. The process of treating potatoes Which comprises impregnating thesame in a comminuted state with a bisulfite, desiccating 10 the Wholemass and recovering starch.

10. The process of treating potatoes Which comprises impregnating thesame in a comminuted state with calcium bisulfite, desiccating the wholemass and recovering starch. v

In testimony whereof, I aflix my signature in the presence of twosubscribing Witnesses.

M. C. MAssIE, Jorm H. Srcenrs.

